The invention relates to a bearing arrangement for a device comprising a first component which is rotatingly driven round an axis of rotation and a second component which is rotatable relative to the first component at least over a limited angle of rotation round the axis of rotation and rotatingly drivingly connected to the first component. In particular, the invention relates to a bearing arrangement for a dual-mass flywheel with a first flywheel which forms the first component and a second flywheel which is torsionally elastically connected to the first flywheel via torsional damping means and forms the second component.
A rotatingly driven component, such as a shaft or the like, is usually rotatably mounted on a stationary component, a machine base or a housing, for example, by means of a rolling bearing. The rolling bearing has a gap between its inner race and its outer race through which dirt may penetrate into the bearing or into the housing or lubricant may escape from the bearing or housing. Conventional bearings are therefore sealed by sealing rings, at least on the outside.
In the above-described bearing arrangement, only the inner race which guides the shaft rotates, whereas the outer race is stationary. The peripheral speed at which the rolling members of the bearing rotate is comparatively low. Consequently, the fluid pressure to which the sealing rings are subjected is also comparatively low. In a plurality of applications, however, in particular in the field of automotive engineering, both components which are mounted on one another rotate not only relative to one another but also jointly round an axis of rotation. Lubricant contained in the bearing is thus subjected to centrifugal forces which make increased demands on the seal. One example for a device with two-components which rotate both jointly and relative to one another is a dual-mass flywheel which is arranged in the path of the driving torque of the internal combustion engine of a motor vehicle, wherein a first flywheel connected to the crankshaft and a second flywheel rotatably mounted relative to the first flywheel via the bearing arrangement are torsionally elastically connected by means of a torsional vibration damper. Further examples of such devices are fluid friction clutches for driving radiator fans or gear transmission arrangements rotating as a unit for driving auxiliary units of an internal combustion engine, such as those known from U.S. Pat. No. 4,760,905 or British Application 2 234 021 (U.S. Pat. No. 5,147,254).
German Patent 34 42 679 discloses a dual-mass flywheel with two flywheels which are rotatable relative to one another round a common axis of rotation and are torsionally elastically connected to one another via a torsional vibration damper. Whereas a first one of the two flywheels is fastened on the crankshaft of an internal combustion engine of a motor vehicle, a second of the flywheels carries a friction clutch of which it forms the opposing contact plate. The second flywheel is mounted on a bearing attachment of the first flywheel via a ball-bearing. The ball-bearing is sealed from the exterior in a lubricant-tight manner and is thermally insulated from the second flywheel by a sealing and insulating ring arrangement. The sealing and insulating ring arrangement comprises two rings which are substantially L-shaped in cross-section and of which each one engages with an axial ring arm between the outer race of the ball-bearing and a bearing seat formed by the second flywheel and has a radial ring arm. The radial ring arms rest on the lateral faces of the inner race of the ball-bearing and are tensioned against its lateral face by a respective Belleville spring washer. However, such a construction is fairly complicated and demands a relatively large amount of space.